Check the input string if it’s in correct email format or not.

using System.Text.RegularExpressions;

public static bool isEmailAddress(string emailAddress)
{
	string patternStrict = @"^(([^<>()[].,;:s@""]+"
		  + @"(.[^<>()[].,;:s@""]+)*)|("".+""))@"
		  + @"(([[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}"
		  + @".[0-9]{1,3}])|(([a-zA-Z-0-9]+.)+"
		  + @"[a-zA-Z]{2,}))$";

	Regex reStrict = new Regex(patternStrict);
	bool isStrictMatch = reStrict.IsMatch(emailAddress);
	return isStrictMatch;
}